Radio telgraphy and telephony receiver.



G. W. PICKARD.

RADIO TELEGRAPHY AND TELEPHONY RECEWER. APPLICATION FILED OCT. 12. 1915.

ttes t: I Inv ntor: flu ww/v by 0W 0. Atty Patented Nov. 6, 1917.4

UNITED STATES PATENT OFFICE.

GREENLEAF WHITTIER PICKARD, 0F AMESIBURY, MASSACHUSETTS, ASSIGNOR TO WIRELESS SPECIALTY APPARATUS COMPANY, OF BOSTON, MASSACHUSETTS, A COR- PORATION OF NEW YORK.

RADIO TELEGRAPHY AND TELEPHONY RECEIVER.

Specification of Letters Patent.

Patented Nov. 6, 1917.

Original application filed March 28, 1914, Serial No. 827,845. Divided and this application filed October 12, 1915. Serial No. 55,369.

To all whom it may concern:

Be it known that I, GREENLEAF \VHIT'lIEi:

PICKARD, a citizen of the United States of America, and a resident of the town of Ainesbury, Massachusetts, have invented certain new and useful Improvements in Radio Telegraphy and Telephony Receivers, the principles of which are set forth in the following specification and accompanying drawings, which disclose the form of the invention which I now consider to be the best of the various forms in which the principles of the invention may be embodied.

This invention relates to improvements in receiving apparatus for radio telegraphy and telephony, and consists of the apparatus and arrangements thereof disclosed herein, the object of the invention being to provide simplified and more efficient apparatus.

Of the drawings, Figures 1 and 2 are diagrammatic illustrations of the invention.

In Fig. 1. A, 4, G is the antenna circuit. Open circuited coils 5 and 6 are disposed on opposite sides 2'. 6. ends of receiving coil I. But coils 5 and 6 are connected together and are wound in such directions that their outside ends are of opposite potentials, as indicated by the plus and minus signs. Coils 5 and 6 are connected together through detector I), around which telephone T is connected. The coupling between each of coils 5 and 6 with coil 4, may be varied, as indicated by the double arrows; and both cou plings may be varied simultaneously.

In use, the operator adjusts the relations of coils et, 5 and 6, and adjusts the detector D until he obtains the best results, as indicated by telephone T, from anygiven trans mission. No adjustment of the inductances of coils 5 and dis needed. If desired, the relation between coils 5 and 6 may be varied widely without any variation of the relations between coils 5 and 4, or 6 and 4, but the relation between coils 5 and 4 or that be-.

tween coils 6 and 4: may be varied also if desired, in addition to the variation of relahaving high resistance and best dperated byv current of high potential, and connected as it is to the ends of coils 5 and 6, subjected to the large potential changes thereat. The detector may be any of the so-called crystal detectors, particularly those of higher resistance, such as my silicon detector; or it may be any other suitable detector.

In Fig. 2, the parts 9, 10,-D and T, and the variable couplings indicated by the double arrows, are the same as in Fig. 1, but coils 9 and 10 have a direction of winding which makes their outside ends of the same instead of opposite potentials, as indicated by the plus signs by way of example. The antennaground circuit A-G has two branches. each containing an adjustable condenser K or K and a receiving coil 7 or 8. The variable coupling of coil 9 is with coil 7, and that of coil 10 is with coil 8. This modification is an embodiment of the-form of Fig. 1, modified to adapt it for combination with an interference preventer which is j of the ordinary form so far as concerns the antenna branch circuits. Thus, by detuning one antenna-branch, say, A, K, 7, Gr signals from distant stations will not have effect on coil 9, but full effect on coil 8. Any aperiodic impulse will divide substantially equally in the two branches of the antenna circuit,

and will therefore cancel out so far as de- I tector D is concerned, on account of the op-- position of coils 9 and 10.

This application is a division of my application Serial Number 827,8l5, filed March 28, 1914,1Patent Number 1,184.376,-granted Mav 23, 1916.

I claim In a radio receiving system, the combination with a receiving coil, of two open-circuited coils disposed on oppositeends of the receiving coil and connected together by way of a detector and having variable couplings with said receiving coil, substantially as and I for the purpose described.

GREENLEAF WHIT'IIEB PICKABD.

Witnesses:

W. R. WARNER, LOUISE M. BRUNS. 

